Environment: Ozone pollution may confuse sex recognition in fruit flies

Exposure to ozone pollution may damage airborne pheromones produced by fruit flies and interfere with their ability to attract a mate or recognise flies of the opposite sex, suggests a Nature Communications paper. The findings highlight another potential threat of human activity on insect populations.

The decline of insect numbers is a major conservation concern in many countries, as numerous species are at risk of extinction. Many insects communicate using pheromones, chemical signals released into the air, which are particularly important for finding a mate. For example, female butterflies and moths are known to use pheromones for attracting males over long distances. However, it is unclear how ground-level ozone — a pollutant produced as a result of industrial emissions — may react with and damage these chemical signals.

Exposing male fruit flies to high levels of ozone was shown to degrade the pheromones produced by the male, Markus Knaden, Nan-Ji Jiang, and colleagues report. Female flies were found to be less interested in these males and much slower to respond to their courtship behaviour. The authors also observed an increase in male-to-male courtship after ozone exposure and suggest that this was likely as a result of the males not being able to differentiate between other males and females without these chemical signals.

The authors note that levels of ozone in our cities are often as high or higher than the levels used in this study. What affect this pollution could be having on wild insect populations requires further research.